I run a headless Pi at work which is given a pretty random internal IP by the DHCP server, so I wanted a way to get the IP pushed to my phone whenever the Pi boots up so I can SSH in.
For this to work you will need an account with http://www.PushBullet.com (it's free) and it setup on your phone (Android or iOS, and again, free!).

You'll notice there's a couple of <>'s to replace in there, you can get these from here (replace the <>'s too!):
Your API for PushBullet is here: https://www.pushbullet.com/account
And to find the device ID of your phone, click on your device on the list on the homepage to send it a note here https://www.pushbullet.com/ and copy the key after the "?device_iden=" part of the URL in your browser.
Add those bits to the script.
Ctrl-X to Save & Quit, then:

You should get a message on your phone with the internal LAN IP address of your Pi.
Note - this is not for external IP - there's plenty of scripts for this, and I'm sure you could adapt this easily if you wanted to.
Lastly, add it to your crontab to make it start at boot:

Aah - I've just realised a slight downside with it - the Pi needs internet access in order to push the message out to the pushbullet servers and then they send it onto my phone.
(Rather than direct across the LAN)

I found this out when trying a robot out in a school - I switched on and got no message on my phone (even though I'd added my home SSID to the WiFi network - perks of being the network manager

I realised in this case that no msg was going across the LAN and that I prob needed to add pushbullet.com to our list of allowed URLs.

Once I'd done that and rebooted the Pi - all OK

Simon

Seeking help with Scratch and I/O stuff for Primary age children
http://cymplecy.wordpress.com/ @cymplecy on twitter